Your iPhone Gets Really Hot (or Cold)
Both sweltering and frigid temperatures are bad for your iPhone, but hot temperatures, in particular, are damaging to your battery. Fortunately, if your iPhone stays inside of a building, that’s likely not a problem.
However, if you make the mistake of leaving your iPhone in the sun or a car, the battery is going to suffer. This may be more of an issue for enterprise iPhones used on the job, but either way, keep an eye on your environment.